The look, of course, is a standby for the mom to Prince George, 8 months. Middleton often relies on a striped shirt and her go-to navy J Brand jeans for official appearances like for a SportsAid event in October 2013 and during the London Olympics in July 2012. She's even been known to sport the combo during her off-hours while on vacation.

Want to adopt Middleton's "uniform" for yourself? While the Zara blazer and Me + Em Breton top have sold out after Friday's appearance, the J Brand 811 Jeans are still available for $169 on Jbrandjeans.com as are Stuart Weitzman "Corkswoon" wedges for $398 on StuartWeitzman.com.